function plot_signals(domain, x, y, y_d, signumn, dx)

	% Plot properties.
	lw = 2;

	le = cell(0, 1);

	cla;

	plot(domain, real(x), 'k-');
	le{length(le) + 1} = ['x'];

	h = gca;
	hold on;

	plot(h, domain, real(y), 'r');
	le{length(le) + 1} = ['y'];

	plot(h, domain, real(y_d), 'b-*', 'LineWidth', lw);
	le{length(le) + 1} = ['dy_1/d\epsilon'];

	text(10, 8, sprintf('Max d(y)/dx =%1.1f', max(gradient(y))));

	hold off;

	axis(h, [0 max(domain) -1 10]);
	grid on;
	legend(le, 'Location', 'East');

	xlabel('Distance (m)');
	ylabel('Concentration');

end
